The reputation Windows has as an audio playback and editing platform has
been, not to put too fine a point on it, abysmal. There have been some
improvements over the years. For example, the early audio infrastructure (often
called the audio stack) seen in Windows 3.1 (16-bit) and Windows 95 (32-bit)
supported only one audio stream at a time, but Windows 98 enabled multiple
playback streams using the Windows Driver Model architecture.

However, Windows audio has always suffered from three major problems:

A poor interface for controlling audio and for troubleshooting audio
problems. Tools such as Volume Control, the Sound Recorder, and the Control
Panel Sounds and Audio Devices icon had difficult interfaces and limited
functionality, and clearly weren't geared for the day-to-day audio tasks
that users face.

Poor quality playback and recording. The Windows audio stack has always
been merely "good enough." That is, audio in Windowsparticularly playbackwas
constructed to give the average user a reasonable level of quality. However,
the default Windows audio had nowhere near the fidelity audiophiles and
professional audio users require, so these users spent much of their time
working around inherent audio limitations (or giving up on Windows
altogether and moving to the Mac).

Poor reliability, to the point that audio glitches are one of main
causes of system instability. The problem here has been that much of the
audio stack code runs in the sensitive Windows kernel mode, where a buggy
driver or process can bring down the entire system.

To address these problems, the Vista audio team completely rewrote the audio
stack from the ground up. That's good news for both regular users and
audiophiles because it means the Vista audio experience should be the best yet.
Completely revamping the audio infrastructure was a big risk, but the aim was to
solve the three previous problems.

We'll have to wait and see if Microsoft accomplished this ambitious goal (not
all the new audio features were available as I wrote this), but on paper, things
look promising:

New tools for controlling the volume, recording sounds, and setting
sound and audio device properties offer a much improved user interface
geared toward common user tasks and troubleshooting audio problems.

The new audio stack offers much higher sound quality.

Most audio code has been moved from kernel mode to user mode, which
should greatly reduce audio-induced system instabilities.

The Volume Control tool in previous versions of Windows is a good example of
poor audio system design. When you opened Volume Control, you were presented
with a series of volume sliders labeled Master, Wave, Line In, CD Player,
Synthesizer, Aux, and more. For the average user, most of these labels were, at
best, meaningless and, at worst, intimidating. What on earth does the Aux slider
control? What's the deal with Line In?

Most people ignored all the sliders except Master and just used that slider
to control playback volume. However, that Master slider had problems of its own.
For example, suppose you're waiting for an important email message, so you set
up Windows Mail to play a sound when an email message comes in. Suppose further
that you're also using Windows Media Player to play music in the background.

If you get a phone call, you want to turn down or mute the music. In previous
versions of Windows, muting the music playback also meant muting other system
sounds, including your email program's audio alerts. So while you're on the
phone, there's a good chance that you'll miss that important message you've been
waiting for.

The
Windows Vista solution to this kind of program is called per-application
volume control. This means that Vista gives you a volume control slider for
every running program and process that is a dedicated sound application (such as
Windows Media Player or Media Center) or is currently producing audio output.

In our example, you'd have separate volume controls for Windows Media Player
and Windows Mail. So when that phone call comes in, you can turn down or mute
Windows Media Player while leaving the Windows Mail volume as is, so there's
much less chance that you'll miss that incoming message.

In the old Volume Control tool, when you adjusted the Master slider, the
other volume sliders remained the same. In the Vista Volume Control tool, when
you move the speaker volume slider, the program sliders move along with it.
That's a nice touch, but what's even nicer is that the speaker volume slider
preserves the relative volume levels of each program. So if you adjust the
speaker volume to about half its current level, the sliders in the application
mixer also adjust to about half of their current level.

Volume Control also remembers application settings between sessions. So if
you mute Solitaire, for example, it will remain muted the next time you start
the program. The new volume control also supports metering, in which the current
audio output is displayed graphically on each slider.

This metering appears as a green wedge that grows taller and wider the louder
the sound signal is. This is very useful for troubleshooting audio problems
because it tells you whether a particular program is actually producing audio
output. If you have no sound from a program, but you see the metering in
program's volume slider, the problem lies outside of the program (for example,
your speakers are turned down or unplugged).

Sound Recorder

The Sound Recorder accessory first appeared in Windows 95 and has remained a
part of Windows ever since. Unfortunately, the Sound Recorder in Windows XP is
essentially the same program as the original version, which means the program's
annoying limitations haven't changed, either:

You can save your recording only using the WAV file format.

You can record only up to 1 minute of sound.

Windows Vista comes with a completely new version of Sound Recorder that does
away with these limitations. For example, you can save your recording using the
Windows Media Audio (WMA) format, and there is no limit (other than available
hard disk space) to the length of the recording.

Having no recording limit might sound dangerous, but the new Sound Recorder
captures WMA audio at a bit rate of 96Kbps, or about 700KB for a 1-minute
recording. Compare this to a 1-minute CD-quality recording using the old Sound
Recorder, which could easily result in a 10MB file!

Audio Devices and Sound Themes

The Windows Vista replacement for the Control Panel Sound and Audio Devices
icon is Audio Devices and Sound Themes (in the Control Panel, select Hardware
and Sound, Audio Devices and Sound Themes).

The Audio Devices tab shows the playback and recording devices on your
system. The first thing to notice is that you now have a visual reminder of the
default devices for playback and recording in the form of a green checkmark
icon. The checkmark means that the device is the default for all uses.

However, you can also designate a device as the default for specific uses. If
you right-click a device and then click Set as Default For, you get a list that
includes All Uses, General Usage, Music and Movies, and Speech and
Communications. (Here, "General Usage" means any use that doesn't involve
movies, music, speech, and communications.)

Windows Vista also implements a more extensive collection of properties for
each device. Double-clicking a device displays a property sheet. The properties
you see depend on the device. Here's a summary of the tabs you see when you open
the default playback device (although note that not all audio playback devices
support all of these tabs):